Highly rearranged mitochondrial genome in Falcolipeurus lice (Phthiraptera: Philopteridae) from endangered eagles

Abstract

Background Fragmented mitochondrial (mt) genomes and extensive mt gene rearrangements have been frequently reported from parasitic lice (Insecta: Phthiraptera). However, relatively little is known about the mt genomes from the family Philopteridae, the most species-rich family within the suborder Ischnocera. Methods Herein, we use next-generation sequencing to decode the mt genome of Falcolipeurus suturalis and compare it with the mt genome of F. quadripustulatus. Phylogenetic relationships within the family Philopteridae were inferred from the concatenated 13 protein-coding genes of the two Falcolipeurus lice and members of the family Philopteridae using Bayesian inference (BI) and maximum likelihood (ML) methods. Results The complete mt genome of F. suturalis is a circular, double-stranded DNA molecule 16,659 bp in size that contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and three non-coding regions. The gene order of the F. suturalis mt genome is rearranged relative to that of F. quadripustulatus, and is radically different from both other louse species and the putative ancestral insect. Phylogenetic analyses revealed clear genetic distinctiveness between F. suturalis and F. quadripustulatus (Bayesian posterior probabilities = 1.0 and bootstrapping frequencies = 100), and that the genus Falcolipeurus is sister to the genus Ibidoecus (Bayesian posterior probabilities = 1.0 and bootstrapping frequencies = 100). Conclusions These datasets help to better understand gene rearrangements in lice and the phylogenetic position of Falcolipeurus and provide useful genetic markers for systematic studies of bird lice. Graphic abstract

Mitochondrial phylogenomics provides insights into the taxonomy and phylogeny of fleas

“…Accurate differentiation and identification of flea species are essential when diagnosing disease and in fundamental and applied research on these important ectoparasites [ 5 – 9 ]. C. canis and the cat flea C. felis have often been misidentified based on morphology because chaetotaxic variation is common [ 6 ].…”

“…Thus, to date, the phylogenetic relationships of fleas remain unclear. The mitochondrial (mt) genome has been often used in systematics and phylogenetic studies across various taxonomic levels of different ectoparasites due to its nature of maternal inheritance, lack recombination, simple structure and rapid evolutionary rate [ 7 – 9 , 13 ]. However, information on the mt genomes of fleas is limited [ 14 – 18 ], a deficiency which has greatly hindered the study of flea biology, genetics and phylogenetics.…”

The Complete Mitochondrial Genome of the Chicken Body Louse, Menacanthus cornutus, and Evolutionary Patterns of Extensive Gene Rearrangements in the Mitochondrial Genomes of Amblycera (Psocodea: Phthiraptera)

“…Previous studies show that the mt genome of the order Phthiraptera is characterized by drastic mt gene rearrangement [ 11 , 12 , 13 , 14 , 15 ]. As one of the suborders of Phthiraptera, Amblycera also have variable and highly rearranged mt genomes [ 22 ].…”

“…Typically, an animal mt genome is a 14–20 kb double-strand circular DNA molecule containing 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and a control region (CR) regulating the replication and transcription of the mt genome [ 2 , 4 , 9 ]. The majority of insect mt genomes present a relatively conservative gene order, such as that in Drosophila yakuba , which is considered as the putative ancestral pattern of the insect gene arrangement [ 10 ] Yet, with a rapid increase in insect mt genome sequencing in recent years, structural variations with novel gene arrangement patterns have been discovered, especially in the order Phthiraptera [ 11 , 12 , 13 , 14 , 15 ], whose gene rearrangement is the most intense, with almost every single gene rearranged.…”

Positive Correlation of the Gene Rearrangements and Evolutionary Rates in the Mitochondrial Genomes of Thrips (Insecta: Thysanoptera)

“…In Hemiptera, gene rearrangement is restricted to tRNA genes (e.g., trnI or trnT ) [ 3 ], whereas in the order Psocodea, rearrangement involves the translocation of protein-coding genes [ 4 ]. In Phthiraptera, intense gene rearrangement (only one to three conserved gene blocks shared with putative ancestral insects) can take place, with some species having highly fragmented mitogenomes (e.g., Pediculus humanus have 18 minichromosomes) [ 5 , 6 , 7 ]. The mitogenome of most thrips generally have three to eight conserved gene blocks (each block contains two to seven genes), which display the putative ancestral gene order.…”